Windows containers can't access external IP

General Discussions Windows
1

Dear all,

I’m using On-Premise Kubernetes. My Windows node run as a service kubelet, kube-proxy and flanneld.

I’ve set flannel as overlay. I could added windows node to the k8s cluster. The pods are created without problem. I could set dns to the enterprise network properly in cni.conf and it works well.
The problem is that I can not ping or access external IPs like a enterprise oracle database or another network ip from the domains. I can ping other container from the same windows node, but from another linux node I can’t reach it either. I can ping it from that node.

Windows Node IPConfig

   Ethernet adapter vEthernet (Ethernet0):

   Connection-specific DNS Suffix  . :
   Description . . . . . . . . . . . : Hyper-V Virtual Ethernet Adapter #2
   Physical Address. . . . . . . . . : 00-50-56-A4-92-9D
   DHCP Enabled. . . . . . . . . . . : No
   Autoconfiguration Enabled . . . . : Yes
   Link-local IPv6 Address . . . . . : fe80::9c32:e102:2c1d:5b56%22(Preferred)
   IPv4 Address. . . . . . . . . . . : 10.54.192.23(Preferred)
   Subnet Mask . . . . . . . . . . . : 255.255.255.0
   Default Gateway . . . . . . . . . : 10.54.192.1
   DHCPv6 IAID . . . . . . . . . . . : 318787670
   DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-26-59-E2-41-00-50-56-A4-92-9D
   DNS Servers . . . . . . . . . . . : 10.54.248.24
                                       10.54.248.23
   NetBIOS over Tcpip. . . . . . . . : Enabled

Ethernet adapter vEthernet (nat):

   Connection-specific DNS Suffix  . :
   Description . . . . . . . . . . . : Hyper-V Virtual Ethernet Adapter
   Physical Address. . . . . . . . . : 00-15-5D-EF-09-84
   DHCP Enabled. . . . . . . . . . . : No
   Autoconfiguration Enabled . . . . : Yes
   Link-local IPv6 Address . . . . . : fe80::b445:80b3:f0eb:8fa2%24(Preferred)
   IPv4 Address. . . . . . . . . . . : 172.22.32.1(Preferred)
   Subnet Mask . . . . . . . . . . . : 255.255.240.0
   Default Gateway . . . . . . . . . :
   DHCPv6 IAID . . . . . . . . . . . : 402658653
   DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-26-59-E2-41-00-50-56-A4-92-9D
   DNS Servers . . . . . . . . . . . : fec0:0:0:ffff::1%1
                                       fec0:0:0:ffff::2%1
                                       fec0:0:0:ffff::3%1
   NetBIOS over Tcpip. . . . . . . . : Enabled

Container IPConfig
Ethernet adapter vEthernet (156b3d454d02f20cda0406077052676b6b43af8e5e5f2d7ee0f0e38914038017_vxlan0):

   Connection-specific DNS Suffix  . : applications.svc.cluster.local
   Description . . . . . . . . . . . : Hyper-V Virtual Ethernet Adapter #5
   Physical Address. . . . . . . . . : 0E-2A-0A-F4-00-10
   DHCP Enabled. . . . . . . . . . . : No
   Autoconfiguration Enabled . . . . : Yes
   Link-local IPv6 Address . . . . . : fe80::f526:18c3:979b:d4bc%65(Preferred)
   IPv4 Address. . . . . . . . . . . : 10.244.0.16(Preferred)
   Subnet Mask . . . . . . . . . . . : 255.255.255.0
   Default Gateway . . . . . . . . . : 10.244.0.1
   DNS Servers . . . . . . . . . . . : 10.96.0.10
                                       10.54.248.24
                                       10.54.248.23
   NetBIOS over Tcpip. . . . . . . . : Disabled
   Connection-specific DNS Suffix Search List :
                                       applications.svc.cluster.local
                                       others-dns.company.local

Could you help us, please?

2

you need to configure worker node with correct CIDR and DNS settings.
check master k8s kube-dns IP address, use that for worker node to setup.
Also try latest windows server 20H2, I have faced similar issue before with win 2019.
So moving to latest windows server helped.